This invention relates to a socket for a printed circuit board into which an edge portion of a printed circuit board is directly inserted to directly form a connector.
Direct-type connectors of various types have been developed in accordance with the recent high-density mount.
Generally, such a connector has a header portion having a plurality of spring contacts. The spring contacts are arranged in a housing made of an insulating material and forming a socket. The contact portions of the spring contacts are projected into an insertion opening for a printed circuit board which is called a daughter board. These contact portions form contact rows arranged at predetermined intervals in the axial direction of the insertion opening. A clearance for fitting the edge portion of the printed circuit board is formed between the contact rows.
To hold the respective contact portions, the insertion opening sides have grooves which are alternately arranged at predetermined intervals, at a pair of opposed walls forming the insertion opening of the header portion. The tops of the contact portions project from the grooves, retreating in the grooves and applying a spring force to the edge portion. The contact portions can come back to their initial positions when the edge portion of the printed circuit board is fitted in the insertion opening. For this reason, the contact portions of the spring contacts certainly contact the contact portion of the printed circuit board and hold the printed circuit board at the header portion by an entire spring force of the spring contacts.
To reliably introduce the edge portion of the printed circuit board into the insertion opening of the header portion, a pair of guide portions are arranged close to both longitudinal ends of the insertion opening. The guide portions guide three surfaces of the printed circuit board along the sides thereof and prevent the edge portion and the header portion from being aligned erroneously.
When the printed circuit board is fitted in the socket, the guide portion guides the three surfaces along the both sides of the printed circuit board. The top edge portion of the printed circuit board is inserted, at a desired attitude and in a desired position, into the insertion opening. Since the contact portions of the spring contacts work as resistors to the edge portion inserted in this manner, the printed circuit board needs to be pushed down with a very strong force against the urging force of the spring contacts. However, since the printed circuit board is guided by the guide portions, it can be reliably pushed down at its predetermined position, without causing erroneous alignment, even when it is pushed with such a strong force.
On the other hand, it is considerably difficult to extract the printed circuit board from a connector of this direct-mode type. This is because the printed circuit board is strongly held between the contacts of the spring contacts, and also because those portions of the board which can be held are limited to a narrow range. Since internal spaces of electronic instruments using such a connector are very limited, particularly due to the mount density increased recently, an eject mechanism for extracting a printed circuit board is desired. In fact, a connector has been developed which incorporates an eject mechanism.
Generally, a printed circuit board is guided between a pair of guide portions. It needs to be extracted parallel with the guide portions. Eject mechanisms are therefore provided at both guide portions for guiding the sides of the printed circuit board.
However, when eject mechanisms are provided at a pair of guide portions, respectively, the connector becomes complicated in structure and comes to have a large size. In order to extract the printed circuit board in parallel, the eject mechanisms must be operated simultaneously. If one eject mechanism is operated prior to the other, the printed circuit board will be inclined between the guide portions. In the worst case, the board will be fixed between the guide portions and will no longer be able to be extracted without difficulty.
This invention has been made in consideration of the above matter. Its object is to provide a simple socket for a printed circuit board, in which the board can be reliably fitted and from which the board can be easily and readily extracted by a simple operation.